#include "myStdio.h"

FILE_* fopen_(const char* path_name, const char* mode)
{
    int flags = 0;
    int defaultMode =0666;
    if(strcmp(mode, "r") == 0)
    {
        flags |= O_RDONLY;
    }
    else if(strcmp(mode, "w") == 0)
    {
        flags |= (O_WRONLY | O_CREAT | O_TRUNC);
    }
    else if(strcmp(mode, "a") == 0)
    {
        flags |= (O_WRONLY | O_CREAT | O_APPEND);
    }
    else 
    {
        
    }
    int fd = 0;

    if(flags & O_RDONLY) fd = open(path_name, flags);
    else fd = open(path_name, flags, defaultMode);
    if(fd < 0)
    {
        const char* err = strerror(errno);
        write(2, err, strlen(err));
        return NULL;
    }
    FILE_* fp = (FILE_*)malloc(sizeof(FILE_));
    assert(fp);

    fp->flags = SYNC_LINE;  //默认设置成为行刷新
    fp->fileno = fd;
    fp->cap = SIZE;
    fp->size = 0;
    memset(fp->buffer, 0, SIZE);

    return fp;
}

void fwrite_(const void* ptr, int num, FILE_* fp)
{
    // 1.写入缓冲区
    memcpy(fp->buffer+fp->size, ptr, num); //这里不考虑缓冲区溢出的问题
    fp->size += num;

    // 2.判断是否刷新
    if(fp->flags & SYNC_NOW)
    {
        write(fp->fileno, fp->buffer, fp->size);
        fp->size = 0;   //清空缓冲区
    }
    else if(fp->flags & SYNC_FULL)
    {
        if(fp->size == fp->cap)
        {
            write(fp->fileno, fp->buffer, fp->size);
            fp->size = 0;   //清空缓冲区
        }
    }
    else if(fp->flags & SYNC_LINE)
    {
        if(fp->buffer[fp->size-1] == '\n')  //不考虑中间有\n的
        {
            write(fp->fileno, fp->buffer, fp->size);
            fp->size = 0;   //清空缓冲区
        }
    }
    else 
    {
        
    }
}

void fflush_(FILE_* fp)
{
    if(fp->size > 0) write(fp->fileno, fp->buffer, fp->size);
    fsync(fp->fileno);  //强制OS刷新
    fp->size = 0;
}

void fclose_(FILE_* fp)
{
   fflush_(fp);
   close(fp->fileno);
}
